package com.farmUni.common;
import java.util.Scanner;
// 1:无需package
// 2: 类名必须Main, 不可修改

public class Test {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        //在此输入您的代码...
        String str =  scan.next();
        String[] numArray = str.split(" ");
        int sum = 0;
        for(int i = 0;i<numArray.length;i++){
            sum += Integer.valueOf(numArray[i]);
        }
        System.out.println(sum/2);
        scan.close();
    }
}
